A blur effect requires render to texture and a custom shader for a post-processing blur effect. That can get complicated and performance will suffer on anything but the latest and greatest devices. A glow effect is easier and can be obtained by adding a bill boarded plane with a transparent texture and additive blending.

If it helps, I just made a glow affect; I'm working on a sort of cloud thing.. which is hard to describe, but at the moment it's a ball of random glowing balls so might be similar to what you're after.

}I created an array of each, with both arrays the same size; I make each Particle the parent to the equivalent Glow, and I make every first item in the particle array the parent of all other particles:

Yes there's quite a few objects in mine! I think the example I gave was using a high number as I was messing around. I've got about 20 of those particles to create a nice glowy cloud. I'm removing the cone now as I found it was a bit pointless and didn't quite do what I wanted so that will decrease it further.